1. Field of the Invention
The present invention relates to backlight units, and more particularly, to a backlight unit and a liquid crystal display device therewith which can increase brightness.
2. Discussion of the Related Art
Among the display devices, there are light emitting display devices, such as cathode ray tubes, organic electro-luminescence display devices, plasma display devices PDP, and so on, and light receiving type display devices which can not emit a light to require a light source additionally, such as liquid crystal display devices.
A liquid crystal display device is provided with two display plates each having an electric field generating electrode and a layer of liquid crystals having dielectric anisotropy. A desired image can be obtained by applying a voltage to the electric field generating electrodes to form an electric field at the liquid crystal layer, and varying the voltage to control an intensity of the electric field to control a transmissivity of the light passing through the liquid crystal layer. The light may be from an artificial light source provided separately, or a natural light source.
In general, as the light source of the liquid crystal display device, a plurality of lamps are used, such as fluorescent lamps like external electrode fluorescent lamps EEFL, or cold cathode fluorescent lamps CCFL, or light emitting diodes LED, for directing a light throughout the liquid crystal display panel uniformly from a rear of the liquid crystal display panel.
Light emitting diode LED backlight unit for the liquid crystal display device, of which research and development is underway actively presently, enable the fabrication of thin display devices, and production of near-natural color. In order to utilize the advantages, production of a high brightness is required. However, the random arrangement of the LEDs or a LED package having luminous fluxes different from one another in the related art fails to provide adequate brightness to a central portion of the image.